Field of the Invention
The present invention is broadly concerned with processing systems and methods for food or feed materials, and particularly food or feed formulations containing high meat contents. The systems include an extruder operable to initially process and heat the formulations, with a downstream processor designed to complete the cooking and formation of final products. The processor includes an elongated processor barrel presenting an inner surface, with a central body within the processor barrel presenting an outer surface, thereby defining an annular region between the inner and outer surfaces. An elongated, rotatable processing element is located within the region about the central body, and has elongated scraping elements in the form of vanes or ribs. During processing, extrudates from the upstream extruder are passed through the annular region of the processor while the inner and outer surfaces of the processor are heated and the processing element is rotated. The final products from the processor may be collected by gravitation or through the use of a die assembly.
Description of the Prior Art
Many human foods or animal feeds are produced using extrusion equipment. For example, the majority of pet and aquatic feeds are extruded products. In general, extrusion equipment and processing parameters are well known in the art for conventional products, such as standard pet feeds containing quantities of protein, fats, and starch. Moreover, such extruded feeds can be supplemented with relatively small amounts of meats using known equipment and processing techniques.
In recent years, however, there has been a demand for extruded products containing relatively high quantities of meat, on the order of 30-40% by weight or greater. For example, many pet owners have expressed a desire for “humanized” pet foods, which have the appearance of meat and similar products normally consumed by humans. Despite these demands, incorporation of these large quantities of meat into extruded products has proved to be difficult, requiring expensive equipment upgrades and sophisticated processing. In fact, 40% meat levels in extruded pet feeds has heretofore proved to be virtually impossible for any reasonable cost.
There is accordingly an unsatisfied need in the art for improved processing systems and methods allowing the high capacity, relatively low cost production of food or feed products having high meat contents.
Prior art references include U.S. Pat. Nos. 3,694,227, 3,883,672, 4,126,177, 4,272,466, 5,228,775, 5,964,278, 5,074,125, 7,097,345, 7,811,617, 7,922,384, and 8,628,815; US Published Application No. 2014/0037812; foreign references EP2733453 and RU2409993; and the following non-patent references: “Extrusion Systems: Components” http://digitalcommons.unl.edu/cgi/viewcontent.cgi?article=1312&context=biosysengfacpub (Accessed Jun. 30, 2015); and “Extrusion Cooking and Related Technique” http://www.wiley-vch.de/books/sample/3527328882_c01.pdf (Accessed Jun. 30, 2015).